The present invention relates to a plant for physical and/or chemical treatment of products in a treatment space(chamber). The products are supported on carriers which are conveyed through the treatment space in a vertical direction; they enter said space through at least an inlet and are discharged from the space through at least one outlet station. The treatment space(chamber) includes driven conveying members for the vertical movenent of the carriers. Such a plant is known per se in various versions. With respect hereto, reference is made to German Patent Specification 749,043 and to U.S. Pat. No. 3,864,846.